Systems for detecting and positioning of reversing valve

ABSTRACT

A heating and cooling system includes a reversing valve configured to adjust a flow of refrigerant through the heating and cooling system, where the reversing valve includes a first configuration to flow the refrigerant through a first circuit of the heating and cooling system and a second configuration to flow the refrigerant through a second circuit of the heating and cooling system. The heating and cooling system also includes a controller configured to determine an operating parameter of a compressor of the heating and cooling system, where the controller is configured to adjust operation of the compressor based on the operating parameter to adjust a position of the reversing valve.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of U.S.Provisional Application Ser. No. 62/662,599, entitled “SYSTEMS FORDETECTING AND POSITIONING OF REVERSING VALVE”, filed Apr. 25, 2018,which is hereby incorporated by reference.

BACKGROUND

The present disclosure relates generally to heating, ventilation, andair conditioning (HVAC) systems, and specifically, to detecting andpositioning a reversing valve in HVAC systems.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described below. This discussion is believed to be helpful inproviding the reader with background information to facilitate a betterunderstanding of the various aspects of the present disclosure.Accordingly, it should be understood that these statements are to beread in this light, and not as admissions of prior art.

Environmental control systems are utilized in residential, commercial,and industrial environments to control environmental properties, such astemperature and humidity, for occupants of the respective environments.The environmental control system may control the environmentalproperties through control of an air flow delivered to and ventilatedfrom the environment. For example, an HVAC system may transfer heatbetween the air flow and refrigerant flowing through the system. TheHVAC system may use a reversing valve that changes position to directcirculation of the refrigerant through the HVAC system. It is nowrecognized that a reversing valve may not fully shift or change itsposition to direct the refrigerant as desired.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

In one embodiment, a heating and cooling system includes a reversingvalve configured to adjust a flow of refrigerant through the heating andcooling system, where the reversing valve includes a first configurationto flow the refrigerant through a first circuit of the heating andcooling system and a second configuration to flow the refrigerantthrough a second circuit of the heating and cooling system. The heatingand cooling system also includes a controller configured to determine anoperating parameter of a compressor of the heating and cooling system,where the controller is configured to adjust operation of the compressorbased on the operating parameter to adjust a position of the reversingvalve.

In one embodiment, a heating and cooling system includes a compressor, areversing valve, and a controller. The compressor is configured topressurize a refrigerant flowing through a refrigerant circuit of theheating and cooling system, where the refrigerant circuit comprises afirst flow path and a second flow path. Additionally, the reversingvalve is configured to adjust flow of the refrigerant through therefrigerant circuit, where the reversing valve includes a firstconfiguration to direct the refrigerant through the first flow path anda second configuration to direct the refrigerant through the second flowpath. Furthermore, the controller is configured to determine anoperating parameter of the compressor, where the controller isconfigured to adjust operation of the compressor based on the operatingparameter to adjust a position of the reversing valve.

In one embodiment, a heating and cooling system includes a reversingvalve configured to direct refrigerant through a refrigerant circuit ofthe heating and cooling system, where the refrigerant circuit includes afirst flow path and a second flow path and where the reversing valveincludes an internal slider configured to transition between a firstposition to direct the refrigerant through the first flow path and asecond position to direct the refrigerant through the second flow path.The heating and cooling system also includes a controller configured todetermine a pressure differential and/or determine an operatingparameter of a motor coupled to a compressor, where the controller isconfigured to adjust operation of the compressor based on the pressuredifferential and/or the operating parameter to adjust the internalslider of the reversing valve.

DRAWINGS

Various aspects of this disclosure may be better understood upon readingthe following detailed description and upon reference to the drawings inwhich:

FIG. 1 is a schematic of an environmental control for buildingenvironmental management that may employ one or more HVAC units, inaccordance with an aspect of the present disclosure;

FIG. 2 is a perspective view of an embodiment of the environmentalcontrol system of FIG. 1, in accordance with an aspect of the presentdisclosure;

FIG. 3 is a schematic of a residential heating and cooling system, inaccordance with an aspect of the present disclosure;

FIG. 4 is a schematic of an embodiment of a vapor compression systemthat can be used in any of the systems of FIGS. 1-3, in accordance withan aspect the present disclosure;

FIG. 5 is a schematic of an embodiment of an HVAC system that uses areversing valve and is configured to monitor pressure differentials, inaccordance with an aspect the present disclosure;

FIG. 6 is a schematic of an embodiment of the HVAC system of FIG. 5configured to monitor compressor motor parameters, in accordance with anaspect the present disclosure;

FIG. 7 is a flowchart of an embodiment of a method to determine andadjust a reversing valve via pressure differential, in accordance withan aspect the present disclosure; and

FIG. 8 is a flowchart of an embodiment of a method to determine andadjust a reversing valve via compressor motor parameters, in accordancewith an aspect the present disclosure.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, not all featuresof an actual implementation are described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The present disclosure is directed to heating, ventilating, and airconditioning (HVAC) systems that use reversing valves to directrefrigerant through a refrigerant circuit within the HVAC system. Forexample, the reversing valve may include a set of conduits that therefrigerant flows through and an internal slider within the reversingvalve that adjusts, opens, or occludes openings in the set of conduits.Depending on the position of the internal slider, the refrigerant flowsthrough the conduits in a certain manner and along a particular flowpath, which results in the refrigerant flowing through the remainingcomponents of the HVAC system in a particular circulation, direction, orflow path.

In some embodiments, the internal slider shifts positions to changeoperating modes of the HVAC system. For example, during a cooling mode,the internal slider may be at a first position to direct the refrigerantto flow through a first circuit, direction, or flow path of therefrigerant circuit. During a heating mode, the internal slider may beat a second position to direct the refrigerant to flow through a secondcircuit, direction, or flow path of the refrigerant circuit. Theinternal slider may be shifted via pressure differential and/or massflow from the refrigerant. For example, the reversing valve may becoupled to a solenoid valve. The solenoid valve is configured to directa portion of pressurized refrigerant to flow from the compressor intothe reversing valve. During an energized state of the reversing valve,when the solenoid valve is actuated via electricity, the portion of therefrigerant flows into the reversing valve at a first side, and thepressurized refrigerant pushes against the internal slider to shift theinternal slider into a first position. During a relaxed state of thereversing valve, when the solenoid valve is not actuated, therefrigerant flows into the reversing valve at a second side, which maybe opposite or substantially opposite to the first side, and thepressurized refrigerant pushes against the internal slider to shift theinternal slider into a second position away from the first position.However, if the flow of the refrigerant or the pressure differential ofthe refrigerant is low, the pressurized refrigerant may not fully shiftthe internal slider into proper position to direct the refrigerant asdesired. For example, when the compressor is operating at a slow speedand/or a low stage, the mass flow and/or the pressure of the refrigerantmay not be high enough to shift the internal slider. This may result ininefficient operations of the HVAC system.

Thus, in accordance with certain embodiments of the present disclosure,it is presently recognized that detecting the position of the internalslider and automatically adjusting the internal slider when the positionis not fully shifted may increase the efficiency of the HVAC system.Specifically, monitoring compressor operating parameters, such aspressure differential and compressor motor parameters, may enable adetermination of whether the internal slider is in the desired or properposition in a manner that is faster and more accurate than traditionalmethods, such as methods that utilize monitoring of temperature of airflow and/or refrigerant. In other words, operation of the compressor maybe adjusted or modified based on an operating parameter of thecompressor to adjust the internal slider of the reversing valve. As usedherein, “based on” includes embodiments in which operation of thecompressor is adjusted or modified based at least in part on anoperating parameter of the compressor to adjust the internal slider ofthe reversing valve. For example, if the compressor operating parametersare below corresponding threshold values, further action may beperformed to shift the internal slider into the desired position. Insome embodiments, the compressor operation is increased. As used herein,increasing the compressor operation includes adjusting the compressoroperations such that the mass flow and/or pressure of refrigerantdischarged from the compressor increases.

Turning now to the drawings, FIG. 1 illustrates a heating, ventilating,and air conditioning (HVAC) system for building environmental managementthat may employ one or more HVAC units. In the illustrated embodiment, abuilding 10 is air conditioned by a system that includes an HVAC unit12. The building 10 may be a commercial structure or a residentialstructure. As shown, the HVAC unit 12 is disposed on the roof of thebuilding 10; however, the HVAC unit 12 may be located in other equipmentrooms or areas adjacent the building 10. The HVAC unit 12 may be asingle packaged unit containing other equipment, such as a blower,integrated air handler, and/or auxiliary heating unit. In otherembodiments, the HVAC unit 12 may be part of a split HVAC system, suchas the system shown in FIG. 3, which includes an outdoor HVAC unit 58and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigerationcycle to provide conditioned air to the building 10. Specifically, theHVAC unit 12 may include one or more heat exchangers across which an airflow is passed to condition the air flow before the air flow is suppliedto the building. In the illustrated embodiment, the HVAC unit 12 is arooftop unit (RTU) that conditions a supply air stream, such asenvironmental air and/or a return air flow from the building 10. Afterthe HVAC unit 12 conditions the air, the air is supplied to the building10 via ductwork 14 extending throughout the building 10 from the HVACunit 12. For example, the ductwork 14 may extend to various individualfloors or other sections of the building 10. In certain embodiments, theHVAC unit 12 may be a heat pump that provides both heating and coolingto the building with one refrigeration circuit configured to operate indifferent modes. In other embodiments, the HVAC unit 12 may include oneor more refrigeration circuits for cooling an air stream and a furnacefor heating the air stream.

A control device 16, one type of which may be a thermostat, may be usedto designate the temperature of the conditioned air. The control device16 also may be used to control the flow of air through the ductwork 14.For example, the control device 16 may be used to regulate operation ofone or more components of the HVAC unit 12 or other components, such asdampers and fans, within the building 10 that may control flow of airthrough and/or from the ductwork 14. In some embodiments, other devicesmay be included in the system, such as pressure and/or temperaturetransducers or switches that sense the temperatures and pressures of thesupply air, return air, and so forth. Moreover, the control device 16may include computer systems that are integrated with or separate fromother building control or monitoring systems, and even systems that areremote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. Inthe illustrated embodiment, the HVAC unit 12 is a single package unitthat may include one or more independent refrigeration circuits andcomponents that are tested, charged, wired, piped, and ready forinstallation. The HVAC unit 12 may provide a variety of heating and/orcooling functions, such as cooling only, heating only, cooling withelectric heat, cooling with dehumidification, cooling with gas heat, orcooling with a heat pump. As described above, the HVAC unit 12 maydirectly cool and/or heat an air stream provided to the building 10 tocondition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2, a cabinet 24 enclosesthe HVAC unit 12 and provides structural support and protection to theinternal components from environmental and other contaminants. In someembodiments, the cabinet 24 may be constructed of galvanized steel andinsulated with aluminum foil faced insulation. Rails 26 may be joined tothe bottom perimeter of the cabinet 24 and provide a foundation for theHVAC unit 12. In certain embodiments, the rails 26 may provide accessfor a forklift and/or overhead rigging to facilitate installation and/orremoval of the HVAC unit 12. In some embodiments, the rails 26 may fitinto “curbs” on the roof to enable the HVAC unit 12 to provide air tothe ductwork 14 from the bottom of the HVAC unit 12 while blockingelements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluidcommunication with one or more refrigeration circuits. Tubes within theheat exchangers 28 and 30 may circulate refrigerant, such as R-410A,through the heat exchangers 28 and 30. The tubes may be of varioustypes, such as multichannel tubes, conventional copper or aluminumtubing, and so forth. Together, the heat exchangers 28 and 30 mayimplement a thermal cycle in which the refrigerant undergoes phasechanges and/or temperature changes as it flows through the heatexchangers 28 and 30 to produce heated and/or cooled air. For example,the heat exchanger 28 may function as a condenser where heat is releasedfrom the refrigerant to ambient air, and the heat exchanger 30 mayfunction as an evaporator where the refrigerant absorbs heat to cool anair stream. In other embodiments, the HVAC unit 12 may operate in a heatpump mode where the roles of the heat exchangers 28 and 30 may bereversed. That is, the heat exchanger 28 may function as an evaporatorand the heat exchanger 30 may function as a condenser. In furtherembodiments, the HVAC unit 12 may include a furnace for heating the airstream that is supplied to the building 10. While the illustratedembodiment of FIG. 2 shows the HVAC unit 12 having two of the heatexchangers 28 and 30, in other embodiments, the HVAC unit 12 may includeone heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separatesthe heat exchanger 30 from the heat exchanger 28. Fans 32 draw air fromthe environment through the heat exchanger 28. Air may be heated and/orcooled as the air flows through the heat exchanger 28 before beingreleased back to the environment surrounding the rooftop unit 12. Ablower assembly 34, powered by a motor 36, draws air through the heatexchanger 30 to heat or cool the air. The heated or cooled air may bedirected to the building 10 by the ductwork 14, which may be connectedto the HVAC unit 12. Before flowing through the heat exchanger 30, theconditioned air flows through one or more filters 38 that may removeparticulates and contaminants from the air. In certain embodiments, thefilters 38 may be disposed on the air intake side of the heat exchanger30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing thethermal cycle. Compressors 42 increase the pressure and temperature ofthe refrigerant before the refrigerant enters the heat exchanger 28. Thecompressors 42 may be any suitable type of compressors, such as scrollcompressors, rotary compressors, screw compressors, or reciprocatingcompressors. In some embodiments, the compressors 42 may include a pairof hermetic direct drive compressors arranged in a dual stageconfiguration 44. However, in other embodiments, any number of thecompressors 42 may be provided to achieve various stages of heatingand/or cooling. As may be appreciated, additional equipment and devicesmay be included in the HVAC unit 12, such as a solid-core filter drier,a drain pan, a disconnect switch, an economizer, pressure switches,phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. Forexample, a high voltage power source may be connected to the terminalblock 46 to power the equipment. The operation of the HVAC unit 12 maybe governed or regulated by a control board 48. The control board 48 mayinclude control circuitry connected to a thermostat, sensors, andalarms. One or more of these components may be referred to hereinseparately or collectively as the control device 16. The controlcircuitry may be configured to control operation of the equipment,provide alarms, and monitor safety switches. Wiring 49 may connect thecontrol board 48 and the terminal block 46 to the equipment of the HVACunit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also inaccordance with present techniques. The residential heating and coolingsystem 50 may provide heated and cooled air to a residential structure,as well as provide outside air for ventilation and provide improvedindoor air quality (IAQ) through devices such as ultraviolet lights andair filters. In the illustrated embodiment, the residential heating andcooling system 50 is a split HVAC system. In general, a residence 52conditioned by a split HVAC system may include refrigerant conduits 54that operatively couple the indoor unit 56 to the outdoor unit 58. Theindoor unit 56 may be positioned in a utility room, an attic, abasement, and so forth. The outdoor unit 58 is typically situatedadjacent to a side of residence 52 and is covered by a shroud to protectthe system components and to prevent leaves and other debris orcontaminants from entering the unit. The refrigerant conduits 54transfer refrigerant between the indoor unit 56 and the outdoor unit 58,typically transferring primarily liquid refrigerant in one direction andprimarily vaporized refrigerant in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, aheat exchanger 60 in the outdoor unit 58 serves as a condenser forre-condensing vaporized refrigerant flowing from the indoor unit 56 tothe outdoor unit 58 via one of the refrigerant conduits 54. In theseapplications, a heat exchanger 62 of the indoor unit functions as anevaporator. Specifically, the heat exchanger 62 receives liquidrefrigerant, which may be expanded by an expansion device, andevaporates the refrigerant before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger60 using a fan 64 and expels the air above the outdoor unit 58. Whenoperating as an air conditioner, the air is heated by the heat exchanger60 within the outdoor unit 58 and exits the unit at a temperature higherthan it entered. The indoor unit 56 includes a blower or fan 66 thatdirects air through or across the indoor heat exchanger 62, where theair is cooled when the system is operating in air conditioning mode.Thereafter, the air is passed through ductwork 68 that directs the airto the residence 52. The overall system operates to maintain a desiredtemperature as set by a system controller. When the temperature sensedinside the residence 52 is higher than the set point on the thermostat,or the set point plus a small amount, the residential heating andcooling system 50 may become operative to refrigerate additional air forcirculation through the residence 52. When the temperature reaches theset point, or the set point minus a small amount, the residentialheating and cooling system 50 may stop the refrigeration cycletemporarily.

The residential heating and cooling system 50 may also operate as a heatpump. When operating as a heat pump, the roles of heat exchangers 60 and62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58will serve as an evaporator to evaporate refrigerant and thereby coolair entering the outdoor unit 58 as the air passes over the outdoor heatexchanger 60. The indoor heat exchanger 62 will receive a stream of airblown over it and will heat the air by condensing the refrigerant.

In some embodiments, the indoor unit 56 may include a furnace system 70.For example, the indoor unit 56 may include the furnace system 70 whenthe residential heating and cooling system 50 is not configured tooperate as a heat pump. The furnace system 70 may include a burnerassembly and heat exchanger, among other components, inside the indoorunit 56. Fuel is provided to the burner assembly of the furnace 70 whereit is mixed with air and combusted to form combustion products. Thecombustion products may pass through tubes or piping in a heatexchanger, separate from heat exchanger 62, such that air directed bythe blower 66 passes over the tubes or pipes and extracts heat from thecombustion products. The heated air may then be routed from the furnacesystem 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can beused in any of the systems described above. The vapor compression system72 may circulate a refrigerant through a circuit starting with acompressor 74. The circuit may also include a condenser 76, an expansionvalve(s) or device(s) 78, and an evaporator 80. The vapor compressionsystem 72 may further include a control panel 82 that has an analog todigital (A/D) converter 84, a microprocessor 86, a non-volatile memory88, and/or an interface board 90. The control panel 82 and itscomponents may function to regulate operation of the vapor compressionsystem 72 based on feedback from an operator, from sensors of the vaporcompression system 72 that detect operating conditions, and so forth.

In some embodiments, the vapor compression system 72 may use one or moreof a variable speed drive (VSDs) 92, a motor 94, the compressor 74, thecondenser 76, the expansion valve or device 78, and/or the evaporator80. The motor 94 may drive the compressor 74 and may be powered by thevariable speed drive (VSD) 92. The VSD 92 receives alternating current(AC) power having a particular fixed line voltage and fixed linefrequency from an AC power source, and provides power having a variablevoltage and frequency to the motor 94. In other embodiments, the motor94 may be powered directly from an AC or direct current (DC) powersource. The motor 94 may include any type of electric motor that can bepowered by a VSD or directly from an AC or DC power source, such as aswitched reluctance motor, an induction motor, an electronicallycommutated permanent magnet motor, or another suitable motor.

The compressor 74 compresses a refrigerant vapor and delivers the vaporto the condenser 76 through a discharge passage. In some embodiments,the compressor 74 may be a centrifugal compressor. The refrigerant vapordelivered by the compressor 74 to the condenser 76 may transfer heat toa fluid passing across the condenser 76, such as ambient orenvironmental air 96. The refrigerant vapor may condense to arefrigerant liquid in the condenser 76 as a result of thermal heattransfer with the environmental air 96. The liquid refrigerant from thecondenser 76 may flow through the expansion device 78 to the evaporator80.

The liquid refrigerant delivered to the evaporator 80 may absorb heatfrom another air stream, such as a supply air stream 98 provided to thebuilding 10 or the residence 52. For example, the supply air stream 98may include ambient or environmental air, return air from a building, ora combination of the two. The liquid refrigerant in the evaporator 80may undergo a phase change from the liquid refrigerant to a refrigerantvapor. In this manner, the evaporator 38 may reduce the temperature ofthe supply air stream 98 via thermal heat transfer with the refrigerant.Thereafter, the vapor refrigerant exits the evaporator 80 and returns tothe compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further includea reheat coil in addition to the evaporator 80. For example, the reheatcoil may be positioned downstream of the evaporator relative to thesupply air stream 98 and may reheat the supply air stream 98 when thesupply air stream 98 is overcooled to remove humidity from the supplyair stream 98 before the supply air stream 98 is directed to thebuilding 10 or the residence 52.

It should be appreciated that any of the features described herein maybe incorporated with the HVAC unit 12, the residential heating andcooling system 50, or other HVAC systems. Additionally, while thefeatures disclosed herein are described in the context of embodimentsthat directly heat and cool a supply air stream provided to a buildingor other load, embodiments of the present disclosure may be applicableto other HVAC systems as well. For example, the features describedherein may be applied to mechanical cooling systems, free coolingsystems, chiller systems, or other heat pump or refrigerationapplications.

As noted above, an HVAC system, such as the HVAC system of FIGS. 1-4,may use reversing valves to direct refrigerant through the HVAC system.The reversing valves may use an internal slider that shifts position todirect the refrigerant in a proper or desired manner. In someembodiments, the reversing valve uses a portion of pressurizedrefrigerant to shift the internal slider to the desired position.However, in some instances, the pressure and/or mass flow of thepressurized refrigerant may not be high enough to push against theinternal slider to fully shift the internal slider into the desiredposition. When the internal slider is not in the desired position,certain compressor operating parameters may be below a certain value. Bymonitoring such compressor operating parameters, it may be determined ifthe internal slider is fully shifted into the proper or desiredposition. If the internal slider is not in the desired position,compressor operations may be adjusted, such as to enhance dischargedrefrigerant to further shift the internal slider. For example, enhancingdischarged refrigerant includes an increasing pressure and/or increasingmass flow.

To illustrate an HVAC system using a reversing valve with the disclosedtechniques, FIG. 5 is a schematic of an embodiment of an HVAC system 150that includes a reversing valve 152. As illustrated by FIG. 5, the HVACsystem 150 is in a cooling mode. The reversing valve 152 includes afirst conduit 154, a second conduit 156, a third conduit 158, and afourth conduit 160. The reversing valve 152 also includes an internalslider 162, or other suitable shifting mechanism, that is configured toshift positions to occlude and/or open a combination of the secondconduit 156, third conduit 158, and fourth conduit 160. When in thecooling mode, the reversing valve 152 covers or occludes the secondconduit 156 and the third conduit 158, thereby separating the secondconduit 156 and third conduit 158 from the first conduit 154 and fourthconduit 160 within the reversing valve 152. As a result, refrigerantflows from an indoor coil 164 into the reversing valve 152 through thesecond conduit 156, where the refrigerant is directed by the internalslider 162 to flow out of the third conduit 158 into an inlet of acompressor 166. The compressor 166 pressurizes the refrigerant,effectively heating the refrigerant, then discharges the heated,pressurized refrigerant from an outlet of the compressor 166 into thereversing valve 152 through the first conduit 154. The refrigerant thenflows out of the reversing valve 152 via the fourth conduit 160 and intoan outdoor coil 168, where the refrigerant exchanges heat with ambientair. In the cooling mode, the outdoor coil 168 acts as a condenser tocool the refrigerant, where the cooled refrigerant exists the outdoorcoil 168 through a cooling circuit 170. In the cooling circuit 170, therefrigerant flows through a check valve 172 configured to flow therefrigerant in a direction 174 and into an expansion valve 176. Theexpansion valve 176 depressurizes the refrigerant to further cool therefrigerant, before the refrigerant flows into the indoor coil 164.Within the indoor coil 164, air 178 flows through the indoor coil, wherethe air 178 exchanges heat with the refrigerant to cool the air 178 andheat the refrigerant. The refrigerant then re-enters the reversing valve152 via the second conduit 156 to restart circulation, and the air 178flows out of the HVAC system 150 to cool an area fluidly coupled to theHVAC system 150, such as a room or a zone of a building.

In some embodiments, the compressor 166 is coupled to a motor 180configured to change operation of the compressor 166. For example, themotor 180 is configured to change a compressor speed or a compressorstage to increase or decrease pressurization of the dischargedrefrigerant and/or increase or decrease mass flow of the dischargedrefrigerant. As a result, the pressure and/or mass flow of therefrigerant entering the reversing valve 152 via the first conduit 154may be adjusted. Additionally, there may be an upstream pressure sensor182 positioned upstream of the compressor 166, such as at a low pressureside of the compressor 166, and a downstream pressure sensor 184positioned downstream of the compressor 166, such as at a high pressureside of the compressor 166. The upstream pressure sensor 182 isconfigured to detect pressure of the refrigerant prior to flowing intothe compressor 166, and the downstream pressure sensor 184 is configuredto detect pressure of the refrigerant flowing out of the compressor 166after compression has occurred.

In some embodiments, the HVAC system 150 includes a controller 186 thatis communicatively coupled to the reversing valve 152, the motor 180,the upstream pressure sensor 182, and the downstream pressure sensor184. The controller 186 may include a memory 188 and a processor 190.The memory 188 may be a mass storage device, a flash memory device,removable memory, or any other non-transitory computer-readable mediumthat includes instructions for the processor 190 to execute. The memory188 may also include volatile memory such as randomly accessible memory(RAM) and/or non-volatile memory such as hard disc memory, flash memory,and/or other suitable memory formats. The processor 190 may execute theinstructions stored in the memory 188, in order to adjust operations ofthe motor 180 and/or change the position of the internal slider 162.

In certain embodiments, the controller 186 uses pressure data detectedby the upstream pressure sensor 182 and/or the downstream pressuresensor 184 to determine if the internal slider 162 is in the desired orproper position. For example, the controller 186 may be configured todetermine if the difference in pressure between the pressure datadetected by the upstream pressure sensor 182 and the pressure datadetected by the downstream pressure sensor 184 is above a certainpressure threshold value to indicate the internal slider 162 is fullyshifted in the desired position. A difference in pressure below thethreshold value may indicate the internal slider 162 is not fullyshifted into the proper or desired position. For example, if theinternal slider 162 is not fully shifted, the refrigerant may not flowas desired within the reversing valve 152 and, thus, the refrigerant isnot effectively or efficiently pressurized by the compressor 166. Thus,the controller 186 may detect the inadequate pressure difference and, asa result, adjust operations of the compressor 166 to further shift theinternal slider 162. It should be appreciated that in additional oralternative embodiments, pressure sensors may be disposed in the HVACsystem 150 in other sections, such as adjacent to the indoor coil 164and the outdoor coil 168. As such, the controller 186 may determine ifthe difference in pressure across other sections of the HVAC system isabove the pressure threshold value.

In additional or in alternative embodiments, the controller 186 usesother data to determine if the internal slider 162 is in the desiredposition. FIG. 6 is an embodiment of the HVAC system 150 in a heatingmode and configured to use compressor motor parameter data to determineif the internal slider 162 is in the desired position. During theheating mode, the internal slider 162 is positioned such that the thirdconduit 158 and fourth conduit 160 are separated from the first conduit154 and the second conduit 156 within the reversing valve 152. Thus, therefrigerant may enter the reversing valve 152 via the fourth conduit 160and then exits the reversing valve 152 via the third conduit 156. Afterexiting the reversing valve 152 via the third conduit 158, therefrigerant enters the inlet of the compressor 166, where therefrigerant is pressurized and discharged from the outlet of thecompressor 166 into the reversing valve 152 via the first conduit 154and out of the reversing valve 152 via the second conduit 156 and intothe indoor coil 164. In this configuration, the indoor coil 164 acts asthe condenser, as the air 178 flowing through the indoor coil 164exchanges heat with the refrigerant to cool the refrigerant and heat theair 178. The air 178 may then exit the HVAC system 150 to heat an areafluidly coupled to the HVAC system 150. After being cooled, therefrigerant exits the indoor coil 164 through a heating circuit 252. Inthe heating circuit 252, the refrigerant flows through a check valve 254configured to flow the refrigerant in the direction 174 to an expansionvalve 256 to depressurize the refrigerant. The cooled refrigerant flowsthrough the outdoor coil 168, where the refrigerant exchanges heat withambient air to heat the refrigerant. The heated refrigerant re-entersthe reversing valve 152 via the fourth conduit 160 and exits through thereversing valve 152 via the third conduit 158 to re-enter the inlet ofthe compressor 166 to restart circulation through the HVAC system 150.

In some embodiments, the controller 186 uses a compressor motorparameter to determine if the internal slider 162 is in the desiredposition. For example, the controller 186 determines current input intothe motor 180, current output from a variable speed drive (VSD) 258coupled to the motor 180, torque sensed by the motor 180, anothercompressor motor parameter, or any combination thereof. In someembodiments, the VSD 258, which may be the same or substantially similarto the VSD 92, is configured to adjust operations of the motor 180 andtherefore adjust operations of the compressor 166. That is, the VSD 258is configured to adjust a speed and/or a stage of the operations of thecompressor 166. In some embodiments, the VSD 258 includes a sensor 260configured to detect the compressor motor parameters. As such, the VSDis communicatively coupled to the controller 186 to enable the sensor260 to transmit data associated with the detected compressor motorparameters. In additional or alternative embodiments, the sensor 260 maybe positioned externally to the VSD, such as adjacent to the motor 180or the compressor 166. The sensor 260 may thus be communicativelycoupled to the controller 186 to transmit data to the controller 186.

In some embodiments, the compressor motor parameters are indicative ofwhether or not the internal slider 162 is fully shifted into the desiredposition. For example, if the corresponding compressor motor parametersare below respective threshold values, the controller 186 determines theinternal slider 162 is not in the desired position and thus, adjustsoperations of the compressor 166 to further shift the internal slider162, such as by increasing the pressure of refrigerant. That is, if theinternal slider 162 is not in the desired position, the motor 180 may beoperating using a lower compressor motor parameter to operate thecompressor 166 in pressurizing the refrigerant. As such, a compressormotor parameter below the threshold value may be indicative of theinternal slider 162 in an undesired position.

To illustrate how the HVAC system 150 may shift the position of theinternal slider 162, FIG. 7 is a flowchart of an embodiment of a method300 of using refrigerant pressure differential for shifting the internalslider 162. At block 302, a pressure differential 166 is detected, suchas via the upstream pressure sensor 182 and the downstream pressuresensor 184. The step described at block 302 may continuously beperformed during operation of the HVAC system 150, such that thepressure differential 166 is constantly monitored. At block 304, thepressure differential is compared with the threshold value to determineif the pressure differential is below the threshold value. If thepressure differential is not below the threshold value, no adjustment ofthe operations of the compressor 166 is performed and the pressuredifferential continues to be monitored. If the pressure differential isdetermined to be below the threshold value, it is further determined ifthe compressor 166 is operating at or above an upper limit, as shown atblock 306. For example, it may be determined if the compressor 166 isoperating at or above a particular speed and/or a particular stage, suchas a maximum speed or stage. If the compressor 166 is determined not tobe operating at or above the upper limit, the compressor operation isincreased, as shown at block 310. That is, a speed of the compressor 166and/or a stage of the compressor 166 is increased, such as via the VSD258 and/or the motor 180. As a result, there is an increase of pressureand/or mass flow rate of the refrigerant flowing out of the outlet ofthe compressor 166 to enter the reversing valve 152, such as via thefirst conduit 154. The increased pressure and/or mass flow rate of therefrigerant may be considered an enhanced state of the dischargedrefrigerant. As mentioned above, the increase of pressure and/or massflow of refrigerant entering the reversing valve 152 may push againstthe internal slider 162 to further shift the internal slider 162 intothe desired position.

After increasing the compressor operation, the pressure differential isagain monitored to determine if the pressure differential is below thethreshold value. If the pressure differential still remains below thethreshold value, the steps of block 304, block 306, and block 310 may berepeated to attempt to further shift the internal valve 162. In certainembodiments, the threshold value may be based on a configuration of theHVAC system 150, such as specifications of the motor 180, the compressor166, the refrigerant, any other components of the HVAC system 150, orany combination thereof. In additional or alternative embodiments, thethreshold value is based off operating parameters of the HVAC system150, such as if the HVAC system 150 is in a heating and/or cooling mode,based on a desired rate of airflow through the HVAC system 150, based ona desired temperature of air flowing through the HVAC system 150,another suitable operating parameter of the HVAC system 150, or anycombination thereof. As such, the threshold value may be adjustedaccordingly in HVAC systems 150 of different configurations or evenwithin the same HVAC system 150 based on the operating parameters of theHVAC system 150. In some embodiments, if the pressure differential isdetermined to be above the threshold value after an increase incompressor operation, the compressor operation may be decreased toreturn to operation prior to determining that the pressure differentialwas below the threshold value. That is, the speed and/or the stage ofthe compressor returns to the speed and/or stage before determining theinternal slider 162 was not fully shifted.

In some embodiments, if the compressor operation is determined to be ator above the upper limit, such as a maximum compressor speed, the HVACsystem 150 is shut down, as shown at block 312. That is, the compressoroperation is not increased, since such an increase may put thecompressor 166 in an undesirable state of operation, and the HVAC system150 may therefore shut down operations. In some embodiments, the HVACsystem 150 is flagged, such as to indicate the internal slider 162 isnot fully shifted and to indicate that maintenance is to be performed,such as to shift the internal slider 162.

Another method may be implemented to shift the position of the internalslider 162, as shown in FIG. 8, which is a flowchart of an embodiment ofa method 350 using a compressor motor parameter for shifting theinternal slider 162. At block 352, a compressor motor parameter iscontinuously detected. As noted above, the compressor motor parametermay be an input current into the motor 180, an output current by the VSD258, a torque sensed by the motor 180, another compressor motorparameter, or any combination thereof. At block 354, it is determined ifthe compressor motor parameter is below a threshold value. If thecompressor motor parameter is determined not to be below the thresholdvalue, operation of the compressor 166 may not be adjusted and thecompressor motor parameter continues to be monitored. However, if thecompressor motor parameter is determined to be above the thresholdvalue, operation of the compressor 166 is further analyzed to determineif the compressor 166 is operating above an upper limit, as shown atblock 306. Similar to the method 300, if the compressor 166 isdetermined not to be operating above the upper limit, operation of thecompressor 166 is increased, as shown in block 310, and the step atblock 354 is further performed to determine if the compressor motorparameter remains below the threshold value. If the compressor motorparameter is below the threshold value, the steps of block 354, 306, and310 may be repeated until the compressor motor parameter is below thethreshold value and/or the compressor operation is at or above the upperlimit. If the compressor motor parameter is below the threshold value,the compressor operation may cease to increase and, in some embodiments,the compressor operation returns to operation prior to the determinationthat the compressor motor parameter was below the threshold value.Similar to the method 300, if the compressor operation is at or abovethe upper limit, such as a maximum speed, the HVAC system 150 may shutdown, as shown at block 312, and the HVAC system 150 may be flagged. Aswith the threshold value associated with pressure differential, thethreshold value for compressor motor parameters may be adjusted based onconfiguration of the HVAC system 150, the operating parameters of theHVAC system 150, another specification of the HVAC system 150, or anycombination thereof.

The methods 300 and 350 may be performed by the controller 186, such asby the processor 190. Moreover, the steps of the methods 300 and 350 arenot exhaustive and as such, additional steps not previously describedmay be performed with these techniques. In some embodiments, the methods300 and 350 may be combined such that both the pressure differential andthe compressor motor parameters are used to determine if the internalslider 162 is correctly positioned.

As set forth above, embodiments of the present disclosure may provideone or more technical effects useful in the operation of HVAC systems.For example, the HVAC system uses a reversing valve to controlcirculation of refrigerant flowing through the HVAC system. Thereversing valve may use an internal slider to direct the flow of therefrigerant through the reversing valve and thus, through the remainderof the HVAC system. The present disclosure determines when the internalslider may be positioned incorrectly, such as via pressure differentialand/or compressor motor parameters, and upon such determination, adjuststhe operation of the compressor to adjust the position of the internalslider. For example, compressor operation, such as compressor speedand/or compressor stage, increases to increase the pressure and/or massflow of discharged refrigerant to further shift the internal slider intothe desired position as the refrigerant flows into the reversing valve.The technical effects and technical problems in the specification areexamples and are not limiting. It should be noted that the embodimentsdescribed in the specification may have other technical effects and cansolve other technical problems.

While only certain features and embodiments of the disclosure have beenillustrated and described, many modifications and changes may occur tothose skilled in the art, such as variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, and the like, without materially departing from the novelteachings and advantages of the subject matter recited in the claims.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of thedisclosure. Furthermore, in an effort to provide a concise descriptionof the exemplary embodiments, all features of an actual implementationmay not have been described, such as those unrelated to the presentlycontemplated best mode of carrying out the disclosed embodiments, orthose unrelated to enabling the claimed embodiments. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerous implementationspecific decisions may be made. Such a development effort might becomplex and time consuming, but would nevertheless be a routineundertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure, without undueexperimentation.

1. A heating and cooling system, comprising: a reversing valveconfigured to adjust a flow of refrigerant through the heating andcooling system, wherein the reversing valve comprises a firstconfiguration to flow the refrigerant through a first circuit of theheating and cooling system and a second configuration to flow therefrigerant through a second circuit of the heating and cooling system;and a controller configured to determine an operating parameter of acompressor of the heating and cooling system, wherein the controller isconfigured to adjust operation of the compressor based on the operatingparameter to adjust a position of the reversing valve.
 2. The heatingand cooling system of claim 1, wherein the controller is configured toadjust operation of the compressor in response to a determination that apressure differential is below a threshold value.
 3. The heating andcooling system of claim 2, wherein the controller is configured toincrease a speed of the compressor or to increase a stage of thecompressor based on the pressure differential.
 4. The heating andcooling system of claim 3, wherein the controller is configured todecrease the speed of the compressor or to decrease the stage of thecompressor in response to a determination that the pressure differentialis above the pressure threshold after the determination that thepressure differential is below the threshold value.
 5. The heating andcooling system of claim 3, wherein the controller is configured to shutdown the heating and cooling system in response to the determinationthat the pressure differential is below the pressure threshold and inresponse to a determination that the compressor is operating at an upperlimit.
 6. The heating and cooling system of claim 5, wherein the upperlimit comprises a maximum speed or a maximum stage of the compressor. 7.The heating and cooling system of claim 2, wherein the threshold valueis based on the compressor, the refrigerant, another component of theheating and cooling system, an operating mode of the heating and coolingsystem, a rate of air flowing through the heating and cooling system, adesired temperature of the air, or any combination thereof.
 8. Theheating and cooling system of claim 2, further comprising a first sensorpositioned at a low pressure side of the heating and cooling system andconfigured to detect a first pressure at the low pressure side andcomprising a second sensor positioned at a high pressure side of theheating and cooling system and configured to detect a second pressure atthe high pressure side, wherein the pressure differential is adifference between the first pressure and the second pressure.
 9. Theheating and cooling system of claim 1, wherein the reversing valve isconfigured to be in the first configuration during a cooling mode of theheating and cooling system and wherein the reversing valve is configuredto be in the second configuration during a heating mode of the heatingand cooling system.
 10. The heating and cooling system of claim 1,wherein the operating parameter comprises a current input into a motorconfigured to drive the compressor, a current output from a variablespeed drive (VSD) coupled to the motor, a torque sensed by the motor, orany combination thereof.
 11. A heating and cooling system, comprising: acompressor configured to pressurize a refrigerant flowing through arefrigerant circuit of the heating and cooling system, wherein therefrigerant circuit comprises a first flow path and a second flow path;a reversing valve configured to adjust flow of the refrigerant throughthe refrigerant circuit, wherein the reversing valve comprises a firstconfiguration to direct the refrigerant through the first flow path anda second configuration to direct the refrigerant through the second flowpath; and a controller configured to determine an operating parameter ofthe compressor, wherein the controller is configured to adjust operationof the compressor based on the operating parameter to adjust a positionof the reversing valve.
 12. The heating and cooling system of claim 11,wherein the compressor comprises a motor, and wherein the motor iscoupled to a variable speed drive (VSD) configured to adjust a speed ofthe compressor.
 13. The heating and cooling system of claim 12, whereinthe VSD comprises a sensor configured to measure the operatingparameter.
 14. The heating and cooling system of claim 12, wherein theoperating parameter comprises a current input into the motor, a currentoutput from the VSD, a torque sensed by the motor, or any combinationthereof.
 15. The heating and cooling system of claim 11, wherein thecontroller is configured to adjust operation of the compressor inresponse to a determination that the operating parameter is below athreshold value.
 16. The heating and cooling system of claim 15, whereinthe threshold value is based on the compressor, the refrigerant, anothercomponent of the heating and cooling system, an operating mode of theheating and cooling system, a rate of air flowing through the heatingand cooling system, a desired temperature of the air, or any combinationthereof.
 17. The heating and cooling system of claim 11, furthercomprising a sensor disposed along the refrigerant circuit, wherein thesensor is configured to detect the operating parameter.
 18. The heatingand cooling system of claim 11, wherein, to adjust the position of thereversing valve, the controller is configured to increase a speed of thecompressor to increase a mass flow rate of refrigerant discharged by thecompressor or to increase a stage of the compressor to increase apressure of refrigerant discharged by the compressor.
 19. A heating andcooling system, comprising: a reversing valve configured to directrefrigerant through a refrigerant circuit of the heating and coolingsystem, wherein the refrigerant circuit comprises a first flow path anda second flow path, and wherein the reversing valve comprises aninternal slider configured to transition between a first position todirect the refrigerant through the first flow path and a second positionto direct the refrigerant through the second flow path; a controllerconfigured to determine a pressure differential and/or determine anoperating parameter of a motor coupled to a compressor, wherein thecontroller is configured to adjust operation of the compressor based onthe pressure differential and/or the operating parameter to adjust theinternal slider of the reversing valve.
 20. The heating and coolingsystem of claim 19, wherein the controller is configured to increasepressure or mass flow rate of refrigerant discharged by the compressorto adjust the internal slider between the first position and the secondposition.
 21. The heating and cooling system of claim 20, wherein thecontroller is configured to increase pressure or mass flow rate of therefrigerant discharged by the compressor in response to a determinationthat the pressure differential and/or the operating parameter is below acorresponding threshold value.
 22. The heating and cooling system ofclaim 21, wherein the controller is configured to increase pressure ormass flow rate of refrigerant discharged by the compressor viaincreasing a speed of the compressor to increase the mass flow rate ofthe discharged refrigerant and/or increasing a stage of the compressorto increase the pressure of the discharged refrigerant.
 23. The heatingand cooling system of claim 19, wherein the operating parameter of themotor comprises a current input into the motor, a current output from avariable speed drive (VSD) coupled to the motor, a torque sensed by themotor, or any combination thereof.
 24. The heating and cooling system ofclaim 19, further comprising a first sensor configured to detect theoperating parameter of the motor, a second sensor configured to detect afirst pressure at a low pressure side of the heating and cooling system,and a third sensor configured to detect a second pressure at a highpressure side of the heating and cooling system, wherein the pressuredifferential is a difference between the first pressure and the secondpressure.
 25. The heating and cooling system of claim 19, wherein thecontroller is configured to adjust operation of the compressor via themotor.